Antigenic analysis of the major outer membrane protein of Chlamydia trachomatis with murine monoclonal antibodies

Abstract

We prepared monoclonal antibodies against prototype strains of the 15 serovars of Chiamydia trachomatis and identified a subset of reagents that reacted with the major outer membrane protein(s) (MOMPs) of one or more serovars. We then determined the specificities of these anti-MOMP monoclonal antibodies by radioimmunoassay and immunoblot assays against the 15 serovars of C. trachomatis and a C. psittaci strain. We identified 14 different anti-MOMP antibody specificities, including serovar-, several orders of subspecies-, and species-specific determinants. In addition, one antibody reacted with all C. trachomatis serovars and a C. psittaci strain, indicating the presence of a genus-specific epitope on MOMP. Many of the cross-reactions of the subspecies-specific antibodies were similar to those previously reported by use of the microimmunofluorescence technique. We also observed a number of cross-reactions that were unexpected but consistent with data derived by the microimmunofluorescence test. All antibodies, except the genus-specific antibodies, reacted with whole elementary bodies in a radioimmunoassay, suggesting surface exposure of the epitopes. These data confirm and extend previous observations that MOMPs among C. trachomatis serovars are antigenically complex and diverse. In addition, these data indicate that the cross-reaction patterns of some monoclonal antibodies directed against MOMP are similar to those detected by the microimmunofluorescence test and are consistent with the hypothesis that such determinants are contained within MOMPs.

Mapping antigenic sites on the major outer membrane protein of Chlamydia trachomatis with synthetic peptides

“…Thus the hydrophobicity of the S3 residue might provide potential antibody-binding ability. The immunodominance of S3-VD IV observed in rabbits is probably different from that observed in mice, since the generation of species-reactive MAbs in mice is a rare event (3,20,26,28). Whether S3 is immunodominant or immunorecessive in humans is unknown at this time.…”

“…It has functional roles for the structural integrity of the extracellular infectious elementary body (EB) and porin properties permitting uptake of essential nutrients such as ATP for the intracellular replicatory form, the reticulate body. Other studies (2,3,20,26,27,35,36,39) have demonstrated that the MOMP has discrete regions of antigenicity and immunoaccessibility. Comparative DNA analysis from MOMP genes of three different C. trachomatis serovars revealed that the MOMP has four regions of amino acid variability interspersed among five regions of amino acid conservation (27).…”

Accumulation of chlamydial lipopolysaccharide antigen in the plasma membranes of infected cells

“…The production of murine monoclonal antibodies 1A5 and F221/6C2/C2 has been described previously (3); these antibodies are specific for the major outer membrane proteins of serovars L2 and F, respectively. Antibody 47A2 was recovered following fusion of splenocytes from a BALB/c mouse that had been immunized with elementary bodies of strain L,/434/Bu to the SP2/0-Agl4 cell line as described previously (3). All antibodies were used as unfractionated ascites fluids.…”

Chlamydia psittaciewe abortion agent: complete nucleotide sequence of the major outer membrane protein gene

“…As such it exhibits porin function under redox control [12] and its expression may be essential for EB to RB conversion following infection of the host cell. Antibodies raised to MOMP from C. trachomatis exhibited several different reactivities, revealing the presence of both type (serovar), subspecies, species and genus specific epitopes on the molecule [13,14]. Although C. psittaci and C. trachomatis share less than 10% DNA homology [15], dot blot analysis has revealed significant homology between the MOMP genes of the two species [16].…”